SHORT-AND LONG-TERM FUNCTIONAL VS MORPHOMETRICAL SALIVARY EFFECTS OF IRRADIATION IN A RODENT MODEL

Background. Irradiation-induced salivary damage which results in sever e xerostomia is a well known entity. However; the underlying mechanism of this phenomenon is still considered enigmatic. Materials and Metho ds. We used one of the most studied models, male Wistar rats, and irra diated them to the head and neck region with both a low dose [2.5 Gy] and a high dose [15 Gy] of irradiation. Then we evaluated salivary gla nd function, weight and morphology of both parotid and submandibular g lands in the same animals. Examinations were obtained for the short-te rm [3 days], long-term [40 days] and extended-term [90 days] time poin ts. Results. We found that irradiation with 15 Gy, but not 2.5 Gy, pro foundly affected all salivary parameters evaluated, the parotid gland to a greater extent. At 40 days post- 15 Gy irradiation, parotid acini tissue was reduced by 35% [p<0.01], being replaced by fibrovascular s tromal tissue. This reduction was accompanied by parotid weight and fu nction reduction of 27% [p<0.05] and 58% [p<0.01], respectively. At ni nety days post-15 Gy in irradiation, the parotid and submandibular fun ctions were reduced by 84% [p<0.01] and 62% [p<0.01], respectively, wh ile the gland weights were reduced by 62% [p<0.01] and 39% [p<0.01], r espectively. Conclusion. The accumulated data demonstrate the time and dose dependent effects of irradiation on both parotid and submandibul ar glands. The effects were more profound for the parotid gland and a par-tial correlation between salivary hypofunction and parenchymal des truction was demonstrated.